1. Field of the Invention
The present invention relates to small internal combustion engines, of the type commonly used with lawnmowers, lawn and garden tractors, other working implements, or sport vehicles. In particular, the present invention relates to fuel tanks for such engines.
2. Description of the Related Art
In small internal combustion engines, fuel is typically stored in a fuel tank connected to the engine housing. The fuel tank includes a filler neck with a cap screw-threaded on the filler neck, the cap removable to permit filling of liquid fuel into the fuel tank. An outlet, usually located in the lower portion of the fuel tank, is connected in a suitable manner to an air/fuel mixing device, such as a carburetor or a fuel injector. The fuel tank supplies fuel to the air/fuel mixing device, and the air/fuel mixing device forms an air/fuel intake mixture and delivers the mixture to the intake system of the engine for combustion. During running of the engine, fuel is continuously drawn from the fuel tank by the air/fuel mixing device.
Fuel which is used with small internal combustion engines may occasionally contain a small amount of moisture therein, usually in the form of small droplets of liquid water. Also, it is possible that moisture may enter the fuel tank when same is open, such as when fuel is being filled into the fuel tank, particularly if the engine is used in a highly humid environment or if rain or snow are present. Problematically, moisture in the fuel tank, if allowed to enter the intake system of the engine during combustion, may inhibit good engine performance.
Some known fuel tanks, particularly those used in connection with large engines, include a water trap in a lower portion of the fuel tank. Water droplets, which are more dense than fuel, tend to separate from the fuel and accumulate in the water trap. Some water traps are equipped with valves which may be opened from time to time to drain accumulated water from the water trap. Although these water trap features are useful in collecting water in fuel tanks, same have not proven entirely satisfactory for preventing water from being drawn with the fuel supply from the fuel tank and into the intake system of the engine.
It is therefore desirable to provide a fuel tank for small internal combustion engines, in which any water within the fuel in the tank is prevented from being drawn into the intake system of the engine during running of the engine.